When severing thermoformed articles from a web of plastic material, there exists a need to ensure accurate coaction between male and female cutting dies in order to ensure accurate part removal, as well as to enhance maximum operating speeds of a thermoforming trim press. Accurate tolerancing and tight fit-up between moving components ensures accurate severing of articles so that flanges along a trim edge are uniform and precise. However, small tolerances between sliding parts and accurate fit-up can also result in increased working loads when stroking a trim press platen or die along a die post (or guide post). Accordingly, improvements are needed in the manner in which moving members of a trim press are axially guided and fitted for coaction during a cyclical article severing operation.